What Is MathemaGical Thinking?

“Magical Thinking: The belief, especially characteristic of early childhood and of many mental illnesses, that thoughts, wishes, or special but causally irrelevant actions can cause or influence external events; thinking founded on this belief.” “Mathematical Thinking: The

The Black-Scholes Magic Trick, Explained!

The economist Paul Romer once compared the models used in finance with the tricks used by magicians, whose secrets are protected by the Magician’s Oath. As he wrote in 2015, “A model is like doing a card

It’s A Conspiracy I Tell You!

I don’t believe in conspiracy theories but — whenever you hear the “but” you know exactly what is coming! — there is one story that is rather worrisome, and also something to which one can trivially add

The Prediction Test

The two most famous theories in the field of forecasting are the butterfly effect, and the efficient market hypothesis. Both are theories, not of prediction, but of non-prediction. The butterfly effect was developed by MIT meteorologist and

Simplify!

The following may or may not be factually accurate. It all happened a long time ago. But it is absolutely 100% correct in spirit. Twenty or so years ago I was browsing through the library of Imperial

Perspective

I love watching Dragons’ Den, the programme in which entrepreneurs try to get established business people to invest in their ideas. I love trying to predict which Dragon will say what, how they will negotiate a deal,

Rule #1 Of Investing: Don’t Obey Rule #1

One of the first lessons in any course on investing will be about portfolio construction and the benefits of diversification, how to maximize expected return for a given level of risk. If assets are not correlated then

Cheers!

Now we are going to talk about drink. About time. Specifically the martini. The original classic martini cocktail is two thirds gin, one third dry vermouth shaken with ice (if you are James Bond) or stirred (for

There’s Nothing Better Than The Right Bad News!

There are many quotes by famous people about problems being opportunities. “The block of granite which was an obstacle in the pathway of the weak, became a stepping-stone in the pathway of the strong.” Thomas Carlyle. “Every

The Wealth Manager

Following on from Credit Ratings, here’s a true story about how reassuring mathematical analysis can be. Until it turns out to be baloney. This story is also a warning about experts. Unfortunately, although there’s a lesson here

Credit Ratings

Didn’t you feel proud when your teacher gave you an A+ at school? Or were you a C student, must try harder? Don’t tell us you were an F! My, you’ve done well…considering. Just as teachers grade